Corrosion of ZE41 initiated in the -Mg matrix adjacent to the eutectic micro-constituent and was attributed to micro-galvanic corrosion of the -Mg matrix coupled to the eutectic micro-constituent. The eutectic micro-constituent did not act as a corrosion barrier and did not stop the advance of the corrosion. As a consequence, the -Mg matrix corroded over the whole surface with little corrosion of the inter-connected eutectic micro-constituent.